Screw-lock.



G. B. BURROWS.

SSSSSSSS K.

AAAAAAAAAAAAAAAAAA G. 6, 1909. 4 964,850. Patented July 19, 1910.

L 5 1219.6 F g.6

, wan/eases Invenior flags only QTATES PATENT OFFICE.

CLARENCE B. BURROWS, OF BEVERLY, MASSACHUSETTS, ASSIGNOR TO BEVERLY LOCK-NUT AND LOCK-BOLT COMPANY, A CORPORATION OF MASSACHUSETTS.

SCREW-LOCK.

T 0 all whom it may concern:

Be it known that I, CLARENCE B. BUR- ROWS, a citizen of the United States, and a resident of Beverly, in the county of Essex and State of Massachusetts, have invented an Improvement in Screw-Locks, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to locking devices for screws, being more particularly though not exclusively intended for locking machine screws, bolts, lag screws or the like.

The invention will be best understood by reference to the following description when taken in connection with the accompanying illustration of one specific embodiment thereof, while its scope will be more particularly pointed out in the appended claims.

In the drawings; Figure l is an elevation, partially in section, showing in unlocked position a locking device for a cap screw; Fig. 2 is a similar view showing the same device in locked position; Fig. 3 is a side elevation of the same screw and locking device; Fig. 4: is a plan of the same; Fig. 5 is an end elevation of the indenting key; and Fig. 6 shows in end elevation a modified form of key.

Referring to the drawings and to the embodiment of my invention selected for illus tration, I have there shown an ordinary machine screw having the partially threaded body portion 1 and the hexagonal head 2. This screw is shown as threaded into the screw receiving body 3, which latter is assumed to be of metal, and is provided with means whereby it may be locked in such position against accidental unthreading. For this purpose, the screw is provided with a slot 4 which extends lengthwise the body portion 1 and also lengthwise of and preferably entirely through the longitudinal dimension of the hexagonal head 2. Within the slot there is provided an indenting key 5 having a suitable sliding movement lengthwise the slot, but preferably permanently retained against withdrawal from the open mouth of the slot after its initial installation. The key, which is preferably of hardened steel, is provided with an indenting portion such as the indenting edge 6, which, when the key is depressed from the position shown in Fig. 1 to that shown in Fig. 2, is

Specification of Letters Patent.

Application filed August 6, 1909.

Patented July 19, 1910.

Serial No. 511,642.

adapted to be forced through the open mouth of the slot into the walls of the screw receiving body. For this purpose, the formation of the key and wedge is preferably such as to provide a wedging action between the indenting edge and the walls of the body 3, the bottom 7 of the slot herein being shown as inclined and engaging with a correspondingly inclined edge of the key. In the unlocked position of the key, the latter preferably, though not necessarily, projects slightly above the head of the screw so that if struck on the end with a hammer or other suitable implement the key is driven from the position shown in Fig. l to that shown in Fig. 2, and its indenting edge wedged into the walls of the screw receiving body so as to lock the screw against further turning movement. As shown in Fig. 1, the key may be so proportioned that the outer corner of its head will project just above the chamfered edge of the screw head. The key may then be depressed by striking the outer corner of the head and when depressed, the striking implement may be used to head the corner edges of the screw adjacent the slot over the key head, thereby retaining it in its locked position. Other means for retaining the key may be employed, but the deformation of the metal over the ends of the depressed key is very simple and the metal of the screw head being relatively soft will yield easily when the key is intentionally wedged out.

In order to retain the key a ainst withdrawal from the mouth of the slot any suitable means may be provided, but herein the key, as shown in Figs. 4: and 5, is made with slightly tapered sides, being broader at its base or inner edge than at its outer edge. This fits a correspondingly tapered slot, so that the key is susceptibleof a longitudinal movement only. The slot may be milled with parallel sides or otherwise cut or formed in the screw, and the walls of the heads subsequently squeezed or pressed in and about the key after the latter has been inserted in position.

To facilitate the application as well as the release of the indenting key, the latter is provided with an enlarged head 8, which is preferably flush with the hexagonal walls of the head when the key is in the unlocked position so that it in no wise interferes with the application of a wrench or the like to the screw head. The head of the key 8, however, presents a shouldered portion 9 and the screw head is so recessed, as by cutting away or milling out a portion of the head across the slot, as to present the lower edge of said shouldered portion between the screw receiving body and the overhanging part 10 of the head. This permits the insertion of a suitable implement between the screw head and the screw receiving body and its application to the shouldered portion of the key, whereby the latter may be lifted or wedged out from the position shown in Fig. 2 to the unlocked position of Fig. 1, thereby unlocking the screw so that it may be removed. The screw when thus relased may be locked again, and as often as desired, by the same key, since the latter is preferably retained permanently in the head of the screw.

As shown in the drawings, the indenting edge of the key is inclined or such other construction is adopted as to give a wedging indentation as the key is forced into locking engagement with the screw receiving body. While preferably the indenting edge 6 of the key is beveled as shown, 1f desired a square edge 11 as shown in Fig. 6 may be employed, the two corners of the edge serving to indent the circular walls of the screw receiving hole with sufficient depth to cause the locking engagement of the key with the said walls.

Machine screws and the like are frequently employed where no means is available for locking them against de-threading, as may be done, for example, in the case of a bolt employing a nut fitted with an ordinary nut lock. The above described device affords a simple but effective means for locking such screws in position when required.

IVhile I have herein shown and described, for the sake of illustration, one specific form of my invention, it is to be understood that the invention is not limited to the particular form and arrangement of parts herein shown, or to the application herein made of the same, but that extensive deviations may be made from the details of the described embodiment without departing from the spirit of the invention.

Claims.

1. In a screw lock, the combination with a screw having an open-mouthed slot of an indenting key having a tool engaging portion for withdrawal of the key, the head of the screw being recessed across the slot to expose said tool engaging portion of the key for withdrawal from its locked position.

2. In a screw lock, the combination with a screw of a movable indenting key therefor,

I i 5 said key having a shoulder portion to permit application of a withdrawing implement, and said screw being formed to present a recess exposing said shoulder portion when the key is in its locked position.

3. In a screw lock or the like, the combination with a threaded body part, of a head, there being provided a longitudinal slot in the head and body, an indenting key movable lengthwise of the slot, said key having an indenting portion adapted to be forced through the mouth of the slot into the walls of the screw receiving body, said key also having a shouldered portion and said screw head having a recessed portion exposing the said shouldered portion of the key when in its locked position, thereby permitting the application of a suitable implement to withdraw the key.

4. In a screw lock or the like, the combination with a threaded body part, of a head, there being provided a longitudinal slot in the head and body, and an indenting key retained against withdrawal from the mouth of the slot but adapted to move lengthwise of the same, said key having an indenting edge adapted to be forced by depression of the key through the mouth of the slot into the walls of the screw receiving body, said key having a shouldered portion and said screw head being formed with a recess across the slot and adjacent the screw receiving body, the shouldered portion of said key being exposed in said recess in the locked position of the key.

5. In a screw lock or the like, the combination with a threaded body part, of a head, there being provided a slot extending lengthwise of the body and entirely through the head and having an inclined bottom, and an indenting key retained against withdrawal from the mouth of the slot but adapted to slide lengthwise of the same, said key in its unlocked position projecting out of the slot beyond the screw head and having an inclined indenting edge adapted to be forced by the depression of the key through the mouth of the slot into the walls of the screw receiving body, said key also having a shouldered portion and said screw head being formed to expose said shouldered portion between the screw receiving body and an overlying portion of the screw head when the key is in its locked position.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

CLARENCE B. BURROIVS.

\Vitnesses Fnnnnnio GILBERT BAUER, THOMAS B. Boo'rii. 

